Disjoint array computer

ABSTRACT

A hierarchical array computer architecture comprised of a master computer connected to a plurality of node computers wherein each node has a memory segment. A high speed connection scheme between the master computer and the nodes allows the master computer or individual nodes conditional access to the node memory segments. The resulting architecture creates an array computer with a large distributed memory in which each memory segment of the distributed memory has an associated computing element; the entire array being housed in a blade server type enclosure. The array computer created with this architecture provides a linear increase of processing speed corresponding to the number of nodes.

FIELD OF THE INVENTION

The present invention relates generally to computer architecture andparticularly to a hierarchical array computer.

BACKGROUND OF THE INVENTION

A specialized array of computers appeared in the early 21ist centuryreferred to as blade servers which are most often found in server farmsprocessing web based data such as emails, as described in U.S. Pat. No.6,411,506. The blades in blade servers are relatively small servercomputers grouped in a common chassis called a blade enclosure. In thetypical blade enclosure, the blades share a common power supply and databus which provides the means for the blades to receive and transmit dataand commands. Also included in the blade enclosure is a switch server,sometimes called a management module, which acts as a job controller forthe blades, as described in U.S. Pat. No. 7,209,347.

An example of a blade server is shown in FIG. 1. The blade chassis, 100,includes removable server blades 101 a-n. The blades 101, share a commonbackplane 102 that provides blade power from a power source 103 and ashared communication bus 104 which is usually an Ethernet bus. Allexternal commands and data are shared over the internal communicationbus 104. One or more management modules 105 coordinate the server bladeoperations. An external connection of the communication bus 106 providesthe blades with access to a common memory source 107 such as NAS(Network Attached Storage) storage. The blades 101 a-n typically havetheir own private memory 108 a-n for use in their local processing.

A modification to the server blade management module was a lateraddition to blade enclosures and was added to allow the server blades toaccess a common set of USB devices such as USB memory devices, asdescribed in U.S. Pat. No. 7,412,544. In the cited patent, means areprovided to connect each blade with a plurality of external USB deviceports with a blade server management module acting as the bridge betweenthe blades and the server blade enclosure USB host ports. Due to themultiple types of USB devices such as keyboards, mouse's, CD-ROM's, andUSB sticks, the blade servers can take advantage of many additionalfunctions. A simplified diagram of this use of external USB devices in ablade server is shown in FIG. 2. The additional I/O network of FIG. 2,110, plus additional hardware in the blade server management module,105, allow USB devices 112 a-m to communicate with the server blades 101a-n.

Although blade servers can be viewed as an array of computers, they arenot considered an “array computer” which normally denotes a group ofcomputers that are tightly coupled together both in hardware andsoftware execution, as discussed in “A Decade of RCS” Proc. IEEE Conf.on Design, Automation and Test in Europe (2001). A primary distinctionof an array computer is the “architecture” of the array which describesthe interconnecting path between the different computing nodes making upthe array.

The review article of array computer architectures in reference 4presents the wide range of complex hardware and software implementationsthat are associated with past array processing solutions. A good exampleof an actual array processing computer is the parallel APL machine builtaround 1990 by Jurgen Sauermann, “A Parallel APL Machine”1990 ACM089791-371. FIG. 3 shows a simplified block diagram of the Sauermannmachine. The Sauermann machine 300 has all the elements of an arraycomputer in that a master processor 301 is tightly coupled to an arrayof slave processors 304 via a common communication network 303 and dualported memory 302 that is shared been the master computer and the slaveprocessors. The slave processors also connected to a network an array ofFPGA's 305 that perform mathematical calculations. The Sauermann machinewas dedicated to a specific task of processing programs written in thecomputer scripting language, APL. A few of the Sauermann machines werebuilt and successfully used by the German Post office.

Although a successful project, the Sauermann machine architecture is noteasily adapted to other applications. Its specialized hardware andsoftware are typical of array processing. It is mentioned because thepresent invention grew out of an interest in the target application ofthe Sauermann machine and has led to our attempt to present an arrayprocessing architecture that can be widely used from both a software andhardware standpoint and at the same time provide an architecture whichis highly adaptable for future advances in computer hardware andsoftware.

In addition to arranging computing elements in large connected arrays, amore recent method has been to build single integrated processors whichinclude multiple CPU cores, as described in “Multicore Processors—ANecessity” by Bryan Schauer (csa-discoveryguides-multicore review,9-2008). Multi-core processors such as the ones available from Intel andAMD can greatly increase the speed of computation. But they requirespecial hardware and software to take advantage of the multi coredesign. In addition, they suffer one major fault that increases thecomplexity of programming and slows computation; namely, the access ofall cores to external storage is thru a single physical channel.

The primary goal of an array computer is to take the processing power ofa single computer and create a machine with N computers whose processingspeed is N times faster than a single computer. This simple goal has ledto a wide variety of software and hardware solutions which havegenerally led to complex and or expensive solutions.

The current invention provides means for creating an array computerhoused in a blade server type enclosure that achieves a linear gain inprocessing power with additional computing nodes while providing asimple programming model for array processing by using a hierarchicalcomputer architecture with disjoint computing nodes and a noveldistributed memory structure.

SUMMARY OF THE INVENTION

A hierarchical array computer architecture comprised of a mastercomputer with a large segmented memory that is segmented using disjointhigh speed data channels that connect the master computer to an array ofcomputing nodes to which the memory segments are directly connected. Themaster computer maps the memory segments as an array of mass storageblocks wherein each memory segment is mapped exclusively to either themaster computer or to the computing node to which the memory segment isdirectly connected.

The computing nodes act as servers waiting for commands from theirclient master computer and are used to process the data in theirassociated shared memory segment upon command from the master computer.

The described architecture can also be viewed as distributed storage inwhich each memory segment of the storage is exclusively accessibleeither by a master computer or only one member of an array of computingnodes. The multiple memory controllers which reside in the array ofcomputing nodes provide exceptional memory access speed and an easilyscalable storage array.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Prior Art—A typical blade server enclosure.

FIG. 2: Prior Art—A blade server which provides USB port access to theserver blades.

FIG. 3: Prior Art—The Sauermann Parallel APL Machine

FIG. 4: DAC Computer Architecture showing the connection between themaster computer and the node computers.

FIGS. 5A: the DAC master computer being connected to an array of memorysegments.

FIG. 5B: The DAC master computer being connected to an array ofcomputing nodes.

FIG. 6: The preferred embodiment of a two level DAC computer wherein asingle USB multi-gadget channel between the level 1 master computer andeach level 2 node computer provides both a storage link andcommunication link between the master computer and its connected nodeprocessor.

DETAILED DESCRIPTION

The present invention relates generally to computer architecture andparticularly to a hierarchical array computer. The following descriptionis presented to enable one of ordinary skill in the art to make and usethe invention and is provided in the context of a patent application andits requirements. Various modifications to the preferred embodiment andthe generic principles and features described herein will be readilyapparent to those skilled in the art. Thus, the present invention is notintended to be limited to the embodiment shown but is to be accorded thewidest scope consistent with the principles and features describedherein.

A short acronym, “DAC”, will be used to describe the present invention.The name comes from the phrase, “Disjoint Array Computer”, because a DACcomputer is a parallel array computer wherein an array of computingnodes are connected to a master computer using high speed data channelsthat do not share a common bus. That is, the computing nodes aredisjoint. FIG. 4 shows an embodiment of a hierarchical two level DACcomputer 400.

In FIG. 4, the high speed data paths 402 a-n provide the dual functionof (a) a communication channel between the master computer and each ofthe node computer 403 a-n, and (b) providing the master computer with Nnumber of mass storage memory segments 404 a-n. Each memory segment 404a-n is only addressable by either the master computer 401 oralternatively addressable by the individual computer nodes 403 a-n. Byusing the communication channels 402 a-n, the Master computer and thenodes which level of computing will have sole access the mass storagememory segments 404 a-n. The DAC computer 400 of FIG. 4 provides aunique memory mapping structure in that it allows the creation of alarge segmented memory for the level one master computer 401 whereby thememory segments are accessed using high speed disjoint data channels 402a-n connected to the computing nodes 403 a-n.

FIG. 5A shows how the shared memory appears to the master computer whenthe master computer has sole access to all of the N number of memorysegments. FIG. 5B shows how the master computer views the array of Level2 nodes when all of the nodes have sole access to the memory segments.

This embodiment provides the means of creating a distributed massstorage architecture by allowing many multiple memory blocks each withits own controller to be viewed as a large distributed memory storecontrolled by one memory manager. Thus the DAC memory structure providesa memory store with a linear expansion capability using relatively smallmemory block increases. For example, if the DAC computer of FIG. 4 has32 nodes each with 1TB of SSD Flash drives and these are replaced by 4TBof SSD drives, the total memory as seen by the level one DAC computerhas increased from 32TB to 256TB.

A major benefit of such a distributed storage architecture with eachmemory segment having its own controller is that each memory segment canbe accessed much faster than if the same amount of storage resided inone large store being accessed by a single memory controller.

A second major benefit is that the computing nodes are closely coupledto the data for which they are tasked to process and that this couplingexcludes any conflict with any other node or the master computer.

The dual nature of the individual memory segments to be owned completelyby either by the master computer or alternatively by an isolatedcomputing node is an important element of the DAC design. It allows thesoftware programs in both the master and node computers to completelyown the memory upon which they are accessing and to not have to dealwith interactive problems typically associated with multi-port memory.

The architecture described above and shown in FIG. 4 and FIG. 5A and 5Bis what we refer to as disjoint computing using disjoint memory.

Because the same area of the DAC shared memory of FIG. 4 should not beaccessed at the same time by both the master computer 401 and one of thecomputing nodes 404, means must be provided between the master computerand any given computing node which allows the master computer tocoordinate the exclusive access to the shared memory.

FIG. 6 shows a version of the preferred embodiment of FIG. 4 of the DACcomputer architecture in which the high speed data channel between thelevel one computer 600 and a level 2 node 603 is USB serial channel 602.In this embodiment, the computing node USB device port 604 is connectedto the master computer USB host port 601. The node USB device portdriver supports a three way USB multi-gadget architecture that allowsthe master computer to view its USB host port 601 as being connected tothree different USB gadgets; namely a memory storage block I/O device604 b, an Ethernet port 604 a, and a TTY port 604 c. In this particularembodiment, the USB block I/O device 604 b is mapped to a physicalstorage drive of the computing node 606. The USB gadget virtual Ethernetport 604 a can be used as the command channel between the mastercomputer and the computing node. The USB gadget TTY port 604 c can beused by the master computer to identify and initialize the computingnode.

Although USB connections were used in the above embodiment to connectthe master computer to the computing nodes, other physical buses withsupporting software drivers could be used to connect the master computerto the node computers in a similar manner described above including theuse of custom FPGA's connected to the respective PCIe buses on themaster and node computers.

Web blade servers are often used to process high speed web traffic. Theblade server architecture that was discussed earlier is similar to thepreferred embodiment of the DAC computer shown in FIG. 4. Bothimplementations are normally designed to fit in a standard server rack.Both use a common power supply to power individual processing nodes. Andboth have a manager to control the processing nodes.

However, there are major differences between a standard web blade serverand the preferred embodiments of the DAC computer which have beenpresented. The main communication channel of the blade server for datatransfers is a high speed bus connected to all the blades including theblade management module. Alternatively, the DAC computer uses isolateddata channels between its master computer and the computer nodes. Inaddition, the memory structure of the DAC computer is a novel storagememory that is used to provide both a large segmented memory for the DACmaster computer and alternatively smaller main memory segments for theDAC computing nodes. And finally, the DAC nodes have no direct access tothe external memory outside of the DAC computer enclosure whereas theWeb Server blades directly address external memory through a networkconnection such as an Ethernet network.

The hierarchical DAC computer architecture achieves unparalleledsimplicity in both hardware and software design by keeping completeorthogonality of the memory and communication between the DAC mastercomputer and the DAC computing nodes.

In addition, the physical placement of the segmented storage memory atthe computing nodes allows extremely large storage to be easilycontrolled by a multitude of memory controllers.

Although the present invention has been described in accordance with theembodiments shown, one of ordinary skill in the art will readilyrecognize that there could be variations to the embodiments and thosevariations would be within the spirit and scope of the presentinvention. Accordingly, many modifications may be made by one ofordinary skill in the art without departing from the spirit and scope ofthe appended claims.

What is claimed is:
 1. A hierarchical computer architecture comprising: a master computer and an array of node computers; wherein the master computer is connected to a plurality of node computers, the master computer being connected to each node computer by a separate communication channel such that only the master computer has direct access to any node computer via the communication channel; each of the plurality of node computers having a memory segment that is either accessible by the node computer or alternatively by the master computer; the choice of exclusive access to the memory segment by either the master computer or the node computer being determined by the master computer using the communication channel between the master computer and the node computer; wherein the plurality of node computers act as servers with a common client being the master computer; both the master computer and the plurality of node computers sharing the same enclosure.
 2. The hierarchical computer architecture of claim 1 in which the master computer and the plurality of node computers derive their power from a central power supply in the enclosure.
 3. The hierarchical computer architecture of claim 1 wherein the master computer can communicate commands and receive status from the plurality of node computers using means other the disjoint data channels.
 4. The hierarchical computer architecture of claim 1 wherein each of the plurality of the node computers uses USB device ports residing on the node computer which are interfaced to a plurality of USB host ports on the master computer; each of the plurality of the USB host ports on the master computer mapped to a memory segment on the node computer which is a physical memory store attached to the node computer.
 5. The hierarchical computer architecture of claim 4 in which the USB device ports of the plurality of node computers appear as USB multi-gadget devices to the master computer providing USB storage device(s) and USB communication channels to the master computer.
 6. The hierarchical computer architecture of claim 5 in which the multi-gadget USB devices on the plurality of node computers as seen by the master computer include USB Ethernet ports.
 7. The hierarchical computer architecture of claim 5 in which the multi-gadget USB devices on the plurality of node computers as seen by the master computer include USB TTY ports.
 8. The hierarchical computer architecture of claim 1 wherein the plurality of node computers use communication ports derived from FPGAs connected to PCle ports residing on the plurality of node computers, the FPGA communication ports also providing compatible communication ports to the master computer; wherein each of the compatible communication ports on the master computer providing the master computer access to memory segments which are separately attached to each of the plurality of node computers.
 9. The hierarchical computer architecture of claim 1; wherein a distributed storage memory architecture is created using the hierarchical computer architecture of a master computer connected to an array of node computers; wherein the plurality of node computers each has one or more storage devices that can also be mapped as separately addressable storage devices by the master computer; the collection of which forms a large distributed storage memory for the master computer that is easily scalable and modular in construction. 